Particle detector spatial resolution

ABSTRACT

Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector.

This invention was made with Government support under Contract No.DE-AC03-76SF00098 between the U.S. Department of Energy and theUniversity of California for the operation of the Lawrence BerkeleyLaboratory. The Government has certain rights in this invention.

FIELD OF THE INVENTION

This invention relates to improvements in spatial resolution in particledetectors, and more particularly to a luminescent layer in a particledetector.

BACKGROUND OF THE INVENTION

A luminescent material, such as cesium iodide (CsI), potassium iodide(KI), rubidium iodide (RbI), gallium selenide (Ga_(y) Se), gadoliniumoxysulphate (Gd₂ O₂ S), lanthanum oxysulphate (La₂ O₂ S), cadmiumsulphide (CdS), zinc cadmium sulphide (Zn_(x) Cd_(1-x) S), cadmiumtungstate (CdWO₃), or lead oxide (PbO_(z)), will receive incidentcharged particles or photons of high kinetic energy and convert part orall of this kinetic energy to one or a plurality of photons ofindividual energies lying in the range 1-4 eV. The electromagneticradiation emitted by the luminescent material is not wholly directed ina single forward direction, but is emitted in all directions, althoughnot isotropically. Preferably, most or all of this radiation shouldpropagate in approximately the forward direction, toward a photodiodelayer that will provide an electrical signal indicating arrival of theincident high energy charged particles or photons. For this reason, manyworkers have attempted to promote forward direction emission of photonsby the light-emitting atoms or molecules contained in the luminescentmaterial.

One early approach to compartmentalization of radiation produced in aluminescent layer is disclosed by MacLeod in U.S. Pat. No. 3,041,456,where thin walls, running in two orthogonal directions, of opticallytransparent material are provided between thin adjacent layers orrectangular parallelepipeds of luminescent material.

Another early approach, disclosed by Ligtenberg et al in U.S. Pat. No.3,825,763, provides a substrate of glass or metal (e.g., Al or Ti), onwhich a thin scintillation layer of CsI or Z_(x) Cd_(1-x) S is depositedof unspecified thickness. A separation layer of Al₂ O₃ is deposited onan exposed surface of the scintillation layer, and a photocathode layerof Cs₂ Sb or similar material is deposited on an exposed surface of theseparation layer. The substrate material and the scintillation materialhave respective thermal expansion coefficients of 2-2.5×10⁻⁵ /°C.,respectively, and the substrate is maintained at an elevated temperatureT=150°-200° C. when the scintillation material is deposited thereon. Thesubstrate-scintillation layer combination is then cooled to roomtemperature, and cracks develop in the thin scintillation layer ascooling proceeds. These cracks produce columns of scintillationmaterial, separated by small air or vacuum gaps between adjacent columnsand extending approximately perpendicularly to thesubstrate-scintillation layer interface. The crack structure therebyproduced has a random collection of shapes and associated diameters.

Gudden et al, in U.S. Pat. No. 3,829,378, disclose use of a luminescentlayer on a screen with an absorbing substance deposited thereon whoseabsorption decreases as position varies from the center toward the edgesof the screen. This invention partly compensates for the tendency ofscreen brightness to decrease as one approaches an edge of the screen.

A process for making columnar structures of a luminescent layer on anX-ray screen is disclosed in U.S. Pat. No. 4,069,355 by Lubowski et al.Depressions or valleys are etched at regular intervals in an underlyingsubstrate, and the luminescent material is grown only on the raisedportions of the substrate. The gaps between adjacent columns ofluminescent material are filled with a highly reflecting material orwith another luminescent material.

Sonoda, in U.S. Pat. No. 4,239,791, discloses a method for making ascreen image intensifier. A heated phosphorescent material layer istreated with a colder liquid material, such as acetone, to causedifferential thermal contraction and form a plurality of elongatedcracks in this layer running approximately perpendicular to thesubstrate-phosphorescent layer interface. These cracks are asserted toform optically independent columns of phosphorescent material.

Riihimaki et al disclose an X-ray intensifying screen with a luminescentlayer formed, in an unspecified manner, with a plurality of regularlyspaced grooves therein to capture and guide light produced in theluminescent layer. The grooves run in one direction only, and it isunclear how light is channelled within the air or vacuum gaps (withrefractive index=1) between the luminescent material (with refractiveindex>1).

Van Leunen, in U.S. Pat. No. 4,712,011, discloses use of the columnarstructure produced by the Ligtenberg, et al, invention, and deposits anX-ray-absorbing material in the air/vacuum gaps to absorb X-ray lightincident on a gap. Up to five percent of the weight of the scintillationlayer may be X-ray-absorbing material deposited in the gaps, but nomethod of depositing the X-ray absorbing material is discussed.

A method for vapor deposition of a luminescent layer on a screen forimage intensification is disclosed by Ligtenberg et al in U.S. Pat. No.4,842,894. The vapor deposition crucible is positioned at about 20°relative to the normal to the screen, and gaps formed between columns ofthe luminescent material appear to be elongated bubbles of unspecifiedmaterial (possibly air or a vacuum). The luminescent material apparentlyforms predominantly crystalline columns of this material.

Bates, in Advances in Electronics and Electron Physics, vol. 28A (1969)pp. 451-459, discloses use of crystalline CsI and thermally-inducedcracking of a contiguous substrate, with crack diameter about 0.5 μm. Itis unclear whether the subsequently grown CsI forms into spaced apartcolumns as a result of presence of the substrate cracks.

Stevels and Schrama-dePauw discuss some characteristics of vapordeposited CsI, activated with Na, in Philips Research Reports, vol. 29(1974) pp. 341-352 and 353-362. Cracks are thermally induced in asubstrate, held at a temperature of T=50°-300° C., and a thick or thinCsI(Na) layer is subsequently grown on a cracked surface of thesubstrate. Stevels et al discuss the effects of heat treatment, thickversus thin CsI layers, the substrate material (KI, RbI or other) andaverage diameter of the cracks on columns of CsI that form on thesubstrate surface. The possibility of light channeling in such columnsis discussed.

An X-ray image intensifier, using CsI material formed into irregularcolumns by a cracked mosaic pattern on a substrate, is disclosed byWashida and Sonoda in Advances in Electronics and Electron Physics, vol.52 (1979) pp. 201-207. The possibility of X-ray channeling is discussed,and two types of column spacings are discussed. Maximum improvement ofX-ray intensity, relative to use of a conventional, non-columnarluminescent material, appears to be about 40 percent.

British Patent No. 1,423,935, issued to Philips Electronics andAssociated Industries, Ltd., discloses provision of a mosaic crackstructure in the form of circles, hexagons and rectangles on a substratesurface. Cesium iodide or a similar luminescent material is subsequentlyvapor deposited on this surface. It is unclear whether spaced apartcolumns of this vapor deposited material form as a result of the mosiaccrack structure.

Most or all of the work discussed above relies upon an irregular mosaiccrack structure, formed by thermal mismatch or a similar process, toprovide formation of columns, if any, of a deposited luminescentmaterial. Little or no regularity or control is available for parameterssuch as column diameters, spacing of adjacent columns, or the tendencyof such columns to coalesce if the luminescent material that providescontrol of these parameters and allows flexibility in formation of suchstructures.

SUMMARY OF THE INVENTION

These needs are met by the invention, which provides one or more methodsfor fabricating a sequence of columns of regular, controllable geometryand diameter perpendicular to the interface of the luminescent materialwith an adjacent material. These columns are separated by gaps that maybe evacuate or filled with air, with a light-absorbing material, or witha light-producing or light-reflecting substance. In one embodiment, athin layer of polyimide or other suitable etchable material is depositedon a substrate structure and a sequence of ridges or projections isetched in the polyimide material in a predetermined geometricalstructure. A luminescent material is slowly grown (rate ≦250 μm/hr) onthe ridge-containing surface to produce a plurality of columns separatedby gaps in one or two dimensions. The width of a ridge is variedaccording to the height of the luminescent layer to be grown so that thecolumns do not coalsece. Alternatively, the ridges may be etcheddirectly into a substrate material, such as glass, plastic, metal oramorphous or crystalline silicon or germanium. In a third embodiment,the structure is put together as a "sandwich" of a first set of layerscontaining a photodiode layer and a second set of layers containing aluminescent layer. The columnar structure thus produced reduces by about58 percent the optical spread factor associated with light produced byconversion in the luminescent material, in one embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of one embodiment of apparatusconstructed according to the invention.

FIGS. 2 and 3 are sectional side views illustrating the columns formedin the luminescent layer in FIG. 1.

FIGS. 4, 5, 6, 7 and 8 are schematic top views of triangular,rectangular, hexagonal, ovular and linear ridge patterns constructed onan underlayer according to the invention.

FIG. 9 is a sectional side view of a second embodiment of the apparatusconstructed according to the invention.

FIGS. 10A and 10B are sectional views illustrating a third embodiment ofthe invention.

FIG. 11 is a graphical view illustrating a measure of the improvement inspatial resolution where the invention is used for X-ray and chargedparticle detection.

DESCRIPTION OF THE INVENTION

In a first embodiment 11 of the invention, shown in FIG. 1, a substrate12 is provided on which a photodiode layer 13 is deposited on onesubstrate surface. The substrate material may be glass, plastic, aceramic, a thin metal layer such as Al or Ti, or crystalline oramorphous silicon or germanium, and the photodiode material ispreferably a hydrogenated amorphous column IV semiconductor materialsuch as a-Si:H or a-Ge:H. A transparent, electrically conductive, thinlayer 14 (not drawn to scale) of material such as indium-tin-oxide("ITO"), tin-oxide ("TO"), or another suitable thin metal film is thendeposited on an exposed surface of the photodiode layer 13 with athickness of 1-100 nanometers (nm). The conductive layer 14 is at leastpartly optically transparent and allows passage of electromagneticradiation (photons) of appropriate wavelengths between a luminescentlayer positioned on one side of the conductive layer and a photodiodelayer 13 positioned on the other side of the conductive layer. Thephotodiode layer 13 and conductive layer 14 are contiguous here. Thesubstrate layer 12 may have any appropriate thickness, and thephotodiode layer 13 may have a thickness of 1-10 μm or 10-100 μm foramorphous semiconductor material (e.g., a-Si:H or a-Ge:H) or crystallinesemiconductor material (e.g., c-Si or c-Ge), respectively. Thephotodiode layer 13 has a plurality of electrical traces 21 connected atone end to this layer at regular intervals, and these traces areconnected at their second ends to readout electronics 22 that receivessignals generated within the photodiode layer.

A pattern layer 15 of etchable pattern material 15, such as polyimideresin, SiO₂, or metals such as Al, Cr, Au, Ag, Pd or Pt, of thicknessd=5-20 μm, is then deposited on an exposed surface of the conductivelayer 14 as shown. Portions of the pattern layer 15 are etched toproduce a one-dimensional or two-dimensional sequence of regularlyspaced ridges 16 of the pattern material that project approximatelyperpendicularly to the interface or surface 17 between the conductivelayer 14 and the pattern layer. The ridges 16 have height≈d₁, lateralthickness or width≈d₂, and are spaced apart from adjacent ridges by adistance≈d₃. In a preferred embodiment, these lengths are d₁ =5-20 μm,d₂ =2-20 μm, and d₃ =10-100 μm. The "pitch" of this pattern of ridges,p=d₂ +d₃, may vary from 15 μm to 110 μm. In the etching of the etchablepattern material 15, a small portion of this material may be allowed toremain at the interface 17, as shown in FIG. 1; or the etchable patternmaterial 15 may be removed down to the interface 17, except for theridges 16. In this latter situation, the interface 17 might be coveredwith a thin layer (not shown in FIG. 1) of an etch stop material, suchas a native oxide or silicon nitride, in a manner well known to workersin this art.

The structure is then heated to a low temperature T=50°-400° C.(preferably, T=100°-250° C.), and a luminescent layer 18 of luminescentmaterial, such as CsI,KI, RbI, CdS, CdWO₃, Zn_(x) Cd_(1-x) S, Ga_(y) Se,Gd₂ O₂ S, La₂ O₂ S, PbO_(z) or other suitable luminescent material, isgrown slowly by evaporation at a growth rate≦500 μm/hr (preferably≦250μm/hr) over the interface 17 and ridges 16, to a height d₄ ≈100-1,000μm. This evaporation process produces a sequence of cylinders or columns19 of the luminescent material, separated by air or vacuum gaps 20 ofdiameter d_(gap) <d₂ because of the presence of the ridges 16 of lateralthickness d₂. Use of a low growth rate improves adhesion and lightemission efficiency of the luminescent material. Certain of theluminescent materials may be activated with Na (CsI), with Tl (CsI), orwith a rare earth such as Ce, Pr, Nd or one of the other 11 rare earthelements (Gd₂ O₂ S).

If the thickness d₄ of the luminescent layer 18 is made sufficientlylarge, it is possible that adjacent columns 19 will coalesce in an upperpart of the layer 18, although the columns 19 will be well separatedfrom one another in the lower part of this structure. This isillustrated schematically in FIG. 2. However, if the luminescent layerthickness d₄ is kept sufficiently small (say, d₄ ≦1,000 μm) and theevaporation rate for the luminescent layer 18 is kept small enough, theresulting luminescent layer should consist of columns 19 of luminescentmaterial that are completely separated from one another. For example, aridge that is d₂ =8 μm wide will produce a gap between two adjacentcolumns of CsI material that does not close until the heights of the twoadjacent columns reaches about 450 μm. This effect scales approximatelylinearly with width d₂ of the ridge. Thus, if ridges of lateral width d₂are grown, the thickness d₄ of the luminescent layer should preferablybe no more than 50 d₂ in order to avoid gap closure. However,luminescent layers of thicknesses d₄ =70 d₂, or even d₄ =100 d₂,prepared according to the invention, will provide improved spatialresolution for particle detection. Thus, a ridge of width d₂ =20 μm ispredicted to produce a gap between two adjacent columns of CsI that doesnot close for a column height d₄ =1,000 μm. The other luminescentmaterials mentioned above are believed to behave qualitatively similarlyso that the minimum height required for gap closure scales approximatelylinearly with ridge width d₂.

As illustrated in FIG. 3, energetic particles 23 (high energy photons ormassive charged particles) that are incident upon the embodiment 11(FIG. 1) first encounter the luminescent layer 18, and all or a portionof the kinetic energy of these particles is converted to electromagneticradiation or photons 25, of wavelength λ₀ lying in the range 0.3 μm≦λ₀≦0.7 μm, emitted by the luminescent material. A photon 25 will propagategenerally toward the interface 17 (FIG. 1) and will encounter and/or bereflected from the wall of the column in which that photon wasoriginally produced. If the incidence angle θ of the photon 23 relativeto a local tangent to the column wall is sufficiently large(cscθ≧cscθ_(cr) =n_(L) =refractive index of luminescent material at thatwavelength), the photon 25 will undergo total internal reflection andwill remain within and propagate within the column in which the photonwas originally produced by kinetic energy conversion. If the conversionradiation is assumed to be emitted isotropically by the luminescentmaterial, the trapped fraction f_(T) of this emitted radiation thatundergoes total internal reflection in the forward direction from acolumn wall is determined to be ##EQU1## Table 1 presents the refractiveindices and trapped fractions f_(T) for some luminescent materials ofinterest. Although the fraction f_(T) is less than 0.5, the fact thatmuch of this radiation stays within the column in which it is producedenhances the spatial resolution of the particle detector constructedaccording to the embodiment 11 in FIG. 1. This trapped fraction f_(T) isapproximately independent of the height of a column.

                  TABLE 1                                                         ______________________________________                                        Refractive Index and Trapping Fraction                                        for Luminescent Material Columns                                              Luminescent      Refractive                                                   Material         Index     f.sub.T                                            ______________________________________                                        CsI              1.78      0.22                                               KI               1.68      0.20                                               RbI              1.65      0.20                                               CdS              2.51      0.30                                               Zn.sub.x Cd.sub.1-x S                                                                          2.36 (est.)                                                                             0.29                                               La.sub.2 O.sub.2 S                                                                             1.56      0.18                                               PbO.sub.z        2.3 (est.)                                                                              0.18                                               ______________________________________                                    

FIGS. 4, 5, 6, 7 and 8 are schematic top views of triangular,rectangular, hexagonal, ovular (or circular) and "linear" arrays thatprovide suitable one-dimensional and two-dimensional ridge patterns forthe etchable material 15 used in the embodiment 11 in FIG. 1. The lineararray 51 shown in FIG. 8 produces a sequence of parallel blocks orcolumns extending above the regions 55 and separated by gaps defined bythe ridges 53. More generally, an array of closed polygonal ridges maybe provided to define and promote initial formation of the columns andseparating gaps.

FIG. 9 illustrates a second embodiment 81 of the invention, in which theorder of some of the layers is reversed. A substrate layer 83 ispatterned and etched to provide a sequence of ridges 85 of the substratematerial extending approximately perpendicularly to the adjacent surfaceof the substrate. As before, the substrate layer material may be glass,plastic, thin metal, or crystalline or amorphous silicon or germanium.Alternatively, a thin polyimide layer 84 may be deposited on the exposedsurface of the substrate 83 and used for ridge formation by etching. Aluminescent layer 87, containing luminescent material such as CsI, KI,RbI, CdS, Zn_(x) Cd_(1-x) S, CdWO₃, Ga_(y) Se, Gd₂ O₂ S, La₂ O₂ S orPbO_(z), with or without any of the activators mentioned above, is thenslowly evaporated over the substrate 83 patterned with the ridges 85,with the substrate temperature T being held relatively low atT=100°-250° C. The luminescent material forms into a plurality ofcolumns 89 that are separated by a sequence of air or vacuum gaps 91defined by the ridges 85 as in FIG. 1. A sealant layer 93 of polyimideor similar materials is deposited over the luminescent layer 87, and anoptically transparent conductive layer 95 of ITO or TO is then depositedover the sealant layer 93. Finally, a photodiode layer 97 of a-Si:H,a-Ge:H or mixture thereof is deposited over the conductive layer. Thedimensions d₁, d₂, d₃ and d₄ of the ridges 85 and luminescent layer 87are as in FIG. 1. The sealant layer 93, the conductive layer 95 and thephotodiode layer 97 have preferred thicknesses in the respective ranges5-10 μm, 1-100 nm, and 1-10 μm (or 10-100 μm), respectively. Energeticparticles 99 are incident upon the structure 81 and will pass throughthe luminescent layer 87 before passing through the photodiode layer 97.

FIG. 10A illustrate a third embodiment of the invention, which isinitially constructed as two separate sets of layers. The first set oflayers includes a substrate 101, of arbitrary thickness, with aphotodiode layer 103 of a-Si:H, a-Ge:H (or a combination thereof), c-Sior c-Ge deposited on the first substrate 101. As in the other twoembodiments, the thickness of the photodiode layer may be 1-10 μm foramorphous Si or Ge and 10-100 μm for crystalline Si or Ge. The secondset of layers includes a second substrate 105, on which is deposited aluminescent layer including a plurality of cylinders or columns 107 ofluminescent material, such as CsI, KI, RbI, CdS, Zn_(x) Cd_(1-x) S,CdWO₃, Ga_(y) Se, Gd₂ O₂ S, La₂ O₂ S or PbO_(z),. The columns 107 areseparated by a plurality of one-dimensional or two-dimensional gaps 109that are initially formed using ridges 111. The ridges 111 are in turnformed as in the first or second embodiments, by etching polyimide oranother suitable etchable material or by etching the underlyingsubstrate 105. In FIG. 10B, the first and second set of layers arebrought together as a "sandwich" and are, optionally, held togetherusing a suitable "glue", such as optical grease, Canadian balsam orother suitable material that produces no effluents when this materialcures and hardens. The assembled apparatus, as shown in FIG. 10B withthe associated electronics 113, then functions as a particle detectorwith improved spatial resolution. One advantage of this third embodimentis that the first and second sets of layers may be fabricatedindependently. If a high temperature is needed to fabricate the columnarluminescent layer 107, the photodiode layer 103 is fabricated separatelyand is not subjected to this high temperature. Readout electronics isalso present, but not shown, in FIGS. 2, 3, 9 and 10B.

Example. The following procedure is preferred for producing a ridgepattern in a polyimide layer. The substrate used should be rinsed inde-ionized water at a temperature of T=180° C. for a time intervalΔt=3-10 minutes. Polyimide material, such as DuPont PI 2555, is spun onan exposed surface of the substrate at a rotation rate of about 3500 rpmfor a time interval Δt=30 sec, or for a time sufficient to produce apolyimide layer of an approximate thickness of 3.5 μm. Alternatively,DuPont PI 2722 material, which contains both the polyimide and aphotoresist material, may be used in place of the PI 2555 material. Thesubstrate-polyimide layer combination is then softbaked for about 3 minat a temperature T=90° C. Photoresist, such as KTI 820, is then spun ontop of the polyimide layer at a rotation speed of about 3500 rpm for atime interval Δt=30 sec, or for a time sufficient to produce aphotoresist thickness of 2.5-3.4 μm. The substrate-polyimidelayer-photoresist layer is then softbaked for 2 min. at a temperatureT=120° C. The photoresist is then exposed to ultraviolet radiation inthe desired pattern for about 15 sec, using photolithography equipmentand procedures known in the art. The irradiated photoresist is thenbaked for about 60 sec. and is developed. The photoresist is immersed ina suitable developer, such as Kodak 934, for about 120 sec., then rinsedand dried. The polyimide is etched simultaneously when the photoresistis developed. The resulting ridge structure is then hardbaked or curedfor at least one hour at a temperature of T=280° C., or for one halfhour at T=350° C. The scintillation layer material is then coated on theridge structure to the desired thickness d₄ =100-1,000 μm, using a lowevaporation rate to allow columns of scintillation material to form inconformity to the ridge pattern provided.

FIG. 11 is a graphical view illustrating the improvement in spatialresolution, using the invention in one embodiment. The solid circlesrepresent intensity of light received through a conventional,unstructured layer of CsI of thickness 450 μm with an a-Si:H photodiodelayer and have an associated FWHM of 540 μm about a selected centralposition at x=1,500 μm. The triangles represent intensity of lightreceived through a columnar structure of 450 μm thick CsI, fabricatedaccording to the invention, with an a-Si:H photodiode layer in the sameconfiguration. Here, the FWHM is 230 μm, a reduction of about 58 percentin the point spread width in one dimension; in two dimensions, the pointspread width reduction is estimated to be about 72 percent. A particledetector constructed using the invention disclosed here may resolvelateral spatial separations as small as 10-50 μm.

The gaps 20 or 91 or 109 in FIGS. 1, 2, 9 or 10A/10B may be filled, bycapillary action or otherwise, with a light-absorbing material, such asTe, Sb or Sn (useful for CsI), to reduce the point spread factorassociated with light produced in a luminescent layer column fabricatedaccording to the invention. Using this embodiment, most of the lightthat is not internally reflected within a given column is absorbed bythe material in an adjacent gap and does not appear in another suchcolumn. This will reduce the total amount of light produced andtransmitted by the luminescent layer but will improve the spatialresolution by ensuring that substantially all light produced in a givencolumn of luminescent material will either be absorbed or will propagatewithin that column to the photodiode layer, where associated readoutelectronics 22 (FIG. 1) detects which column of luminescent materialproduced the material. The absorbing material used here should have anoptical absorption edge that reaches its maximum near, but below, therange of wavelengths produced by the luminescent material.

I claim:
 1. A method of producing a detector of X-rays and high energycharged particles with improved spatial resolution, the methodcomprising the steps of:providing a substrate layer of material with anelectrically conductive surface; forming a particle detector layercontaining a-Si:H or a-Ge:H on the conductive surface of the substratelayer; forming a conductive layer of electrically conductive materialthat is at least partly transparent to incident light having awavelength λ in the range 0.3 μm≦λ≦0.7 μm, adjacent to the particledetector layer so that the particle detector layer lies between thesubstrate layer and the conductive layer; forming a pattern formationlayer, having at least a predetermined minimum thickness and containingan etchable material, adjacent to the conductive layer so that theconductive layer lies between the particle detector layer and thepattern formation layer; etching a predetermined pattern in the patternformation layer so that the etchable material forms a plurality ofridges or projections, of lateral width d, on an exposed surface of thepattern formation layer; and forming a scintillation layer, at a growthrate≦500 μm per hour, at a temperature T in the range 50° C.≦T≦400° C.,and of thickness no more than 100 d, of scintillation material thatproduces light of wavelength in the range 0.3-0.7 μm in response toreceipt of high energy particles thereat, whereby the scintillationmaterial forms as cylinders or columns, separated by gaps that conformto the predetermined pattern.
 2. The method of claim 1, furthercomprising the step of choosing said scintillation layer material fromthe class consisting of CsI, KI, RbI, CdS, Zn_(x) Cd_(1-x) S, Gd₂ O₂ S,La₂ O₂ S, Ga_(y) Se, CdWO₃ and PbO_(z).
 3. The method of claim 1,further comprising the step of choosing said conductive layer materialfrom the class consisting of ITO, TO, Al, Cr, Au, Ag Pd and Pt.
 4. Themethod of claim 1, further comprising the step of choosing said patternformation layer material from the class consisting of polyimide,amorphous silicon, crystalline silicon, amorphous germanium orcrystalline germanium.
 5. The method of claim 4, further comprising thestep of choosing said predetermined pattern for said pattern formationlayer from the class consisting of a triangle, a quadrilateral, ahexagon, an oval and a linear array pattern.
 6. The method of claim 1,further comprising the step of filling said gaps between said columnswith a material that is highly absorbing for light of said wavelengthλ₀.
 7. The method of claim 1, further comprising the step of choosingsaid scintillation layer growth rate to be no more than 250 μm per hour.8. The method of claim 1, further comprising the step of choosing saidtemperature T to lie in the range 100° C.≦T≦250° C.
 9. The method ofclaim 1, further comprising the step of choosing said thickness of saidscintillation layer to be no more than 50 d.
 10. The method of claim 1,further comprising the step of choosing said lateral width d to be inthe range 2-20 μm.
 11. A method of producing a detector of X-rays andhigh energy charged particles with improved spatial resolution, themethod comprising the steps of:providing a substrate layer of materialhaving an electrically conductive surface and containing an etchablematerial; etching a predetermined pattern in the conductive surface ofthe substrate so that the etchable material forms a plurality ofprojections of lateral width d on the conductive surface of thesubstrate surface; forming a scintillation layer, at a growth rate≦500μm per hour, at a temperature T in the range 50° C.≦T≦400° C., and ofthickness no more than 100 d, of scintillation material that produceslight of wavelength λ in the range 0.3 μm≦λ≦0.7 μm in response toreceipt of high energy particles thereat; forming a thin layer ofsealant material on an exposed surface of the scintillation layer sothat the scintillation layer lies between the substrate layer and theetchable material layer; forming a conductive layer of electricallyconductive material that is at least partly transparent to incidentlight having a wavelength lying in the range 0.3 μm≦λ≦0.7 μm, adjacentto an exposed surface of the sealant material layer so that the sealantmaterial layer lies between the scintillation layer and the conductivelayer; forming a particle detection layer adjacent to an exposed surfaceof the conductive layer and containing a-Si:H or a-Ge:H, whereby thescintillation material forms as cylinders or columns, separated by gapsthat conform to the predetermined pattern.
 12. The method of claim 11,further comprising the step of choosing said scintillation layermaterial from the class consisting of CsI, KI, RbI, CdS, Zn_(x) Cd_(1-x)S, Gd₂ O₂ S, La₂ O₂ S, Ga_(y) Se, CdWO₃ and PbO_(z).
 13. The method ofclaim 11, further comprising the step of choosing said conductive layermaterial from the class consisting of ITO, TO, Al, Cr, Au, Ag, Pd andPt.
 14. The method of claim 11, further comprising the step of choosingsaid pattern formation layer material from the class consisting ofpolyimide, amorphous silicon, crystalline silicon, amorphous germaniumand crystalline germanium.
 15. The method of claim 14, furthercomprising the step of choosing said predetermined pattern for saidpattern formation layer from the class consisting of a triangle, aquadrilateral, a hexagon, an oval and a linear array pattern.
 16. Themethod of claim 11, further comprising the step of filling said gapsbetween said columns with a material that is highly absorbing for lightof said wavelength λ₀.
 17. The method of claim 11, further comprisingthe step of choosing said scintillation layer growth rate to be no morethan 250 μm per hour.
 18. The method of claim 11, further comprising thestep of choosing said temperature T to lie in the range 100° C.≦T≦250°C.
 19. The method of claim 11, further comprising the step of choosingsaid thickness of said scintillation layer to be no more than 50 d. 20.The method of claim 11, further comprising the step of choosing saidlateral width d to be in the range 2-20 μm.
 21. A method of producing adetector of X-rays and high energy charged particles with improvedspatial resolution, the method comprising the steps of:forming a firststructural component consisting of a first substrate layer of materialand a particle detector layer, containing a-Si:H or a-Ge:H and depositedon an exposed surface of the first substrate layer; forming a secondstructural component by:forming a second substrate layer of materialcontaining an etchable material on an exposed surface; etching apredetermined pattern in the etchable material of the second substratelayer to form a plurality of ridges or projections, of lateral width d,on an exposed surface of the etchable material; and forming ascintillation layer, at a growth rate ≦500 μm per hour, at a temperatureT in the range 50° C.≦T≦400° C., and of thickness no more than 100 d, ofscintillation material that produces light having a wavelength λ lyingin the range 0.3 μm≦λ≦0.7 μm in response to receipt of high energyparticles, so that the scintillation material forms as cylinders orcolumns, separated by gaps that conform to the predetermined pattern;and bringing the first and second structural components together so thatan exposed surface of the particle detection layer is adjacent to anexposed surface of the scintillation layer.
 22. The method of claim 21,further comprising the step of providing an optically transparentmaterial, positioned between said scintillation layer and said particledetection layer, to hold said scintillation layer and said particledetector layer together.
 23. The method of claim 21, further comprisingthe step of choosing said scintillation layer material from the classconsisting of CsI, KI, RbI, CdS, Zn_(x) Cd_(1-x) S, Gd₂ O₂ S, La₂ O₂ S,Ga_(y) Se, CdWO₃ and PbO_(z).
 24. The method of claim 21, furthercomprising the step of choosing said pattern formation layer materialfrom the class consisting of polyimide, amorphous silicon, crystallinesilicon, amorphous germanium or crystalline germanium.
 25. The method ofclaim 21, further comprising the step of choosing said predeterminedpattern for said pattern formation layer from the class consisting of atriangle, a quadrilateral, a hexagon, an oval and a linear arraypattern.
 26. The method of claim 21, further comprising the step offilling said gaps between said columns with a material that is highlyabsorbing for light of said wavelength λ₀.
 27. The method of claim 21,further comprising the step of choosing said scintillation layer growthrate to be no more than 250 μm per hour.
 28. The method of claim 21,further comprising the step of choosing said temperature T to lie in therange 100° C.≦T≦250° C.
 29. The method of claim 21, further comprisingthe step of choosing said thickness of said scintillation layer to be nomore than 50 d.
 30. The method of claim 21, further comprising the stepof choosing said lateral width d to be in the range 2-20 μm. 31.Apparatus for detection of X-rays and high energy charged particles withimproved spatial resolution of detection, the apparatus comprising:afirst substrate, having an electrically conductive surface; a particledetector layer, formed on the conductive surface of the first substrate;an electrically conductive layer, formed on an exposed surface of theparticle detector layer; a scintillation layer, formed on an exposedsurface of the conductive layer as a plurality of columns of luminescentscintillation material that produces light having a wavelength λ lyingin a range 0.3 μm≦λ≦0.7 μm in response to receipt of high energyparticles, with adjacent columns of scintillation material beingseparated by gaps of maximum lateral width d and the columns ofscintillation material having a height no more than 100 d; and a sealantlayer formed over an exposed surface of the scintillation layer, wherethe gaps between the columns of said luminescent scintillation materialconform to a predetermined pattern at the interface between theconductive layer and the scintillation layer, or at the interfacebetween the sealant layer and the scintillation layer.
 32. The apparatusof claim 31, wherein said scintillation layer material is drawn from theclass consisting of CsI, KI, RbI, CdS, Zn_(x) Cd_(1-x) S, Gd₂ O₂ S, La₂O₂ S, Ga_(y) Se, CdWO₃ and PbO_(z).
 33. The apparatus of claim 31,wherein said predetermined pattern is drawn from the class consisting ofa triangle, a quadrilateral, a hexagon, an oval and a linear arraypattern.
 34. The apparatus of claim 31, wherein said height of saidcolumns of said scintillation material is no more than 50 d.